Optical pickup, optical information device, computer, optical disk player, car navigation system, optical disk recorder, and optical disk server

ABSTRACT

To provide an optical pickup and an optical information device, capable of obtaining excellent signal characteristics for an optical disk on and/or from which recording and/or reproducing are performed using a laser. The optical pickup includes an optical detector, a support holder for holding the optical detector, and an optical base for fixing the support holder. The support holder has at least two notches at its both ends, the optical base has convex portions corresponding to the notches of the support holder, the optical base and the support holder are fixed by photo-curable adhesives for bonding the convex portions and the support holder to each other, and the shortest distance between the side faces of the convex portions, which do not face each other, is equal to or less than the width of the support holder in the direction of right and left ends.

This application is a continuation of U.S. patent application Ser. No.12/678,312, filed Mar. 16, 2010, which is incorporated herein byreference.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national phase application of PCTInternational Patent Application No. PCT/JP2008/002580 filed Sep. 18,2008, claiming the benefit of priority of Japanese Patent ApplicationNo. 2007-241893 filed Sep. 19, 2007, all of which are incorporated byreference herein in their entirety.

TECHNICAL FIELD

The present invention relates to an optical pickup and opticalinformation devices which have the optical pickup built therein, andirradiates an optical disk with light to perform recording and/orreproduction of information.

BACKGROUND ART

Although there are various recording media for recording and savingdigital audio, images, animations, document files and data files whichare created by computer, etc., there is an optical disk as one of therecording media. Especially, DVDs (Digital Versatile Disks) have a highdensity and large capacity as compared with conventional CDs (CompactDiscs), and even in the field of picture recording machines, arespreading as media to replace the currently mainstream VTRs (Video TapeRecorders). Moreover, in recent years, BDs (Blu-ray Disks) that are anext-generation optical disk, which have further enhanced recordingdensity using a blue semiconductor laser, are beginning to spread.

In order to increase the capacity of an optical disk, it is necessary toincrease the recording density of information by making an optical spotformed by the light radiated to the optical disk smaller wheninformation is recorded on the optical disk and when the informationrecorded on the optical disk is reproduced. The optical spot can be madesmaller by shortening the wavelength of the laser beam of the lightsource and enlarging the numerical aperture (NA) of an objective lens.In DVDs, a light source with a wavelength of 660 nm and an objectivelens with a numerical aperture (NA) of 0.6 are used. On the other hand,in BDs, a recording density of 5 times the recording density of DVDs isattained by using a blue laser with a wavelength of 405 nm and anobjective lens of NA 0.85. Additionally, in these optical disks, inorder to perform recording and reproducing of data, an opticalinformation device is required.

Meanwhile, as one of the parts which constitute the optical pickup,there is an optical detector for receiving the reflected light from anoptical disk to generate a control signal, a reproduction signal, etc.of the optical pickup. It is necessary to adjust and fix this opticaldetector to a specified position on an optical axis with high accuracy,and a higher accuracy of adjustment and fixation than the conventionaltechnique is required for an optical pickup which performsrecording/reproducing on a higher-density disk. In conventional opticalpickups for DVDs and CDs, the method described below was used as amethod of fixation and adjustment of the optical detector.

For example, in a method shown in Japanese Patent No. 3663141 as aconventional technique, as shown in FIG. 21, cut-in portions 221 a and221 b are formed at both ends of a mounting plate 220 which supports anoptical detector 210, convex portions 231 a and 231 b formed on anoptical base 230 are inserted into the cut-in portions 221 a and 221 bof the mounting plate 220, respectively, and the mounting plate 220 isadjusted in a floating state on the air. After the adjustment isperformed with high accuracy and the position is temporarily determined,the mounting plate 220 is fixed to an optical base 230, usingphoto-curable adhesives, such as UV curable resin.

Here, the convex portions 231 a and 231 b of the optical base 230 haveshapes such that the convex portions stick out from both ends of themounting base 220, and exposed surfaces of the convex portions 231 a and231 b of the optical base 230 and the cut-in portions 221 a and 221 b ofthe mounting plate 220 are adhered to each other.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

However, the present inventor has discovered that there are thefollowing problems when the optical pickup fabricated by theabove-described method is used for BDs.

FIG. 22 is a view showing a graph when characteristics of the opticalpickup fabricated by the above conventional technique are evaluated byusing changes in the value of the focus offset accompanying temporalchanges.

As shown in FIG. 22, in an optical pickup in a state immediately afterthe fabrication, i.e., immediately after the adhesive between themounting plate 220 and the optical base 230 was cured, a focus offset ofabout 0.12 μm occurred from the ideal offset state. Moreover, in orderto investigate the storage durability of this optical pickup, when theoptical pickup was stored and subjected to a progress experiment under ahigh temperature (about 70 to 80° C.), a low temperature (−40 to −30°C.), and a high humidity (a humidity of about 900), the focus offsetfurther increased and occurred as much as about 0.24 μm.

It is believed that the cause of this focus offset is because deviationhas occurred between the ideal position of the optical detector 210 andthe actual arrangement position of the optical detector 210. When theposition of the optical detector 210 was actually measured, a positionaldeviation of about 20 μm occurred.

Generally, if the focus offset amount exceeds 10% of a linear range, theservo becomes unstable and a reproduction signal deteriorates.Therefore, in the optical pickup, it is necessary to suppress the focusoffset amount to the numeric value of 10%. In the case of DVDs, thespacing of the defocusing amount such that a defocusing detection range,i.e., a dynamic range (difference between the smallest and greatest ofFE signal strength) in a focus error (FE) signal becomes the greatest isapproximately 4 μm. Even if the focus offset change after long-termstorage is a value of about 0.24 μm as shown in FIG. 22, this is merelyan amount equivalent to 6% of the linear range of DVDs.

That is, the focus offset is maintained in a range which does not exceedan allowable value even when the optical pickup fabricated by theconventional method is used for DVDs. Therefore, in a case ofreproducing from and/or recording on DVDs, there was no great influenceon reproduction signal characteristics even if the above offset amountoccurred.

However, in the case of high-density optical disks like BDs whichperform reproducing and/or recording using a blue laser beam of shorterwavelength than that of the red laser used for DVDs, the defocusingdetection range is approximately 2 μm which is narrower than that ofDVDs.

Accordingly, in the optical pickup fabricated by the conventionalmethod, in a case where the positional deviation after long-term storageof the optical detector 210 occurs as much as about 20 μm, this becomesan amount equivalent to about 12% of the defocusing detection range ofBDs, and eventually exceeds the focus offset allowable value (10% orless with respect to the defocusing detection range) in BDs.

As described above, according to the conventional optical pickup, thepresent inventor has realized that it is necessary to take thepositional deviation of the optical detector 210, which did not need tobe taken into consideration in the case of DVDs, into consideration inthe case of BDs. Moreover, the present inventor has studied thespecification and solution of the cause of occurrence of positionaldeviation, as will be described later.

The present invention was made in view of such problems, and the objectthereof is to provide an optical pickup and an optical informationdevice using the optical pickup, capable of obtaining excellent signalcharacteristics for an optical disk on and/or from which recordingand/or reproducing are performed using a laser.

Means for Solving the Problems

The 1^(st) aspect of the present invention is an optical pickupcomprising:

an optical component;

a support holder for holding said optical component; and

an optical base for fixing said support holder,

wherein said support holder has at least one concave portion at its bothends, respectively,

said optical base has convex portions corresponding to said concaveportions of said support holder,

said optical base and said support holder are fixed by photo-curableadhesives for adhering said convex portions and said support holder toeach other, and

side faces of a pair of said convex portions are respectively arrangedon the same planes as both said ends of said support holder, said sidefaces not facing each other, and

when the shortest distance between said side faces of said pair of saidconvex portions is defined as W, and a width of both said ends of saidsupport holder in a direction of right and left ends is defined as X,relationship ofX=W

is satisfied.

The 2^(nd) aspect of the present invention is the optical pickupaccording to the 1^(st) aspect of the present invention,

wherein said pair of said convex portions is a pair of prismatic memberswhich protrudes vertically from said optical base,

said pair of side faces which do not face each other is a pair ofparallel faces located outside among said faces of said prismaticmembers vertical to said optical base, and

said shortest distance is a distance between said pair of parallelfaces.

The 3rd aspect of the present invention is the optical pickup accordingto the 1^(st) aspect of the present invention,

wherein application positions of said photo-curable adhesives aresymmetrical to each other in a vertical direction and a horizontaldirection about center of a light-receiving region of said opticalcomponent.

The 4th aspect of the present invention is the optical pickup accordingto the 1^(st) aspect of the present invention,

wherein said concave portions of said support holder form notches whichpass through both surfaces of said support holder.

The 5th aspect of the present invention is the optical pickup accordingto the 1^(st) aspect of the present invention,

wherein said concave portions of said support holder are formed only ina surface side of said support holder which faces said convex portions.

The 6th aspect of the present invention is the optical pickup accordingto the 4th of 5th aspects of the present invention,

wherein a height of said convex portions is a height such that saidconvex portions do not protrude from said support holder in a directionof an optical axis of a beam which enters said optical component.

The 7th aspect of the present invention is the optical pickup accordingto the 6th aspect of the present invention,

wherein said convex portions are hidden inside an external shape of saidsupport holder in a projection view seen from a drawing direction ofsaid convex portion.

The 8th aspect of the present invention is the optical pickup accordingto the 1^(st) aspect of the present invention,

wherein said pair of said convex portions is a pair of columnar memberswhich protrudes vertically from said optical base,

wherein said pair of side faces which do not face each other is a pairof opposed oblique faces or positively bent curved faces located outsideamong faces of said columnar members vertical to said optical base, and

said shortest distance is a distance between roots of said curved facesor oblique faces.

The 9th aspect of the present invention is the optical pickup accordingto the 1^(st) aspect of the present invention,

wherein said convex portions have grooves or banks provided along adrawing direction from said surface of said optical base.

The 10th aspect of the present invention is the optical pickup accordingto the 1^(st) aspect of the present invention,

wherein said convex portions are formed from a transparent material.

The 11th aspect of the present invention is the optical pickupsaccording to the 10th aspect of the present invention,

wherein said faces of said concave portions which face said convexportions are subjected to reflecting processing.

The 12th aspect of the present invention is the optical pickup accordingto the 1^(st) aspect of the present invention,

wherein said adhesive has a viscosity of 20000 mPa·s or more in a gelstate during non-curing.

The 13th aspect of the present invention is the optical pickup accordingto the 1^(st) aspect of the present invention,

wherein hardness of said adhesive after curing is equal to or greaterthan 60 and equal to or less than 90 in Shore D scales.

The 14th aspect of the present invention is the optical pickup accordingto the 1^(st) aspect of the present invention,

wherein said optical component is an optical detector which receives alight beam emitted from a light source and reflected by an optical disk.

The 15th aspect of the present invention is an optical informationdevice comprising:

said optical pickup according to the 1^(st) aspect of the presentinvention,

a motor which turns an optical disk, and

an electric circuit which receives a signal obtained from said opticalpickup, and controls or drives said motor and said optical pickup onsaid basis of said signal.

The 16th aspect of the present invention is a computer comprising:

the optical information device according to the 15th aspect of thepresent invention,

an input device or input terminal for inputting information,

an arithmetic device which performs calculation on said basis ofinformation input from said input device or input terminal, orinformation reproduced from said optical information device, and

an output device or output terminal for displaying or outputting saidinformation input from said input device or input terminal, saidinformation reproduced from said optical information device, or resultscalculated by said arithmetic device.

The 17th aspect of the present invention is an optical disk playercomprising:

the optical information device according to the 15th aspect of thepresent invention, and

a decoder from information to an image, which converts an informationsignal obtained from said optical information device into an image.

The 18th aspect of the present invention is a car navigation systemcomprising:

the optical information device according to the 15th aspect of thepresent invention, and

a decoder from information to an image, which converts an informationsignal obtained from said optical information device into an image.

The 19th aspect of the present invention is an optical disk recordercomprising:

the optical information device according to the 15th aspect of thepresent invention, and

an encoder from said image to information, which converts imageinformation into information to be recorded by said optical informationdevice.

The 20th aspect of the present invention is an optical disk servercomprising:

the optical information device according to the 15th aspect of thepresent invention, and

an input/output terminal which performs exchange of information withoutside.

The 21st aspect of the present invention is an optical pickupcomprising:

an optical component;

a support holder for holding said optical component; and

an optical base for fixing said support holder,

wherein said support holder has at least one concave portion at its bothends, respectively,

said optical base has convex portions corresponding to said concaveportions of said support holder,

said optical base and said support holder are fixed by photo-curableadhesives for adhering said convex portions and said support holder toeach other, and

at least one of side faces of a pair of said convex portions is arrangedat a position further inward than inside said end of said supportholder, said side faces not facing each other, and

when the shortest distance between said side faces of a pair of saidconvex portions is defined as W, said side faces not facing each other,a width of both said ends of said support holder in a direction of rightand left ends is defined as X, and a distance capable of being adjustedin position along a direction of said width is defined as dx,relationship ofX−W≧2dx  (Expression 1)

is satisfied, and

said dx is equal to or less than 300 μm.

Another aspect of the invention is an optical pickup comprising:

an optical component;

a support holder for holding said optical component; and

an optical base for fixing said support holder,

wherein said support holder has at least one concave portion at its bothends, respectively,

said optical base has convex portions corresponding to said concaveportions of said support holder,

said optical base and said support holder are fixed by photo-curableadhesives for adhering said convex portions and said support holder toeach other, and

the shortest distance between side faces of a pair of said convexportions is equal to or less than a width of said support holder in adirection of right and left ends, said side faces do not facing eachother.

The 2^(nd) aspect of the invention is the pickup according to the abovementioned 1^(st) aspect of the invention,

wherein said pair of said convex portions is a pair of prismatic memberswhich protrudes vertically from said optical base,

said pair of side faces which do not face each other is a pair ofparallel faces located outside among said faces of said prismaticmembers vertical to said optical base, and

said shortest distance is a distance between said pair of parallelfaces.

The 3^(rd) aspect of the invention is the optical pickup according tothe above mentioned 2^(nd) aspect of the invention,

wherein

(1) one of said side faces of said convex portion is arranged on thesame plane as said end of said support holder or at a position locatingfurther inward than said end, and the other of said side faces of saidconvex portion is arranged on the same plane as said end of said supportholder or at a position locating further inward than said end, or

(2) one of said side faces of said convex portion is arranged at aposition locating further inward than said end of said support holder,and the other of said side faces of said convex portion is arranged onthe same plane as said end of said support holder or at a positionlocating further outward than said end.

The 4^(th) aspect of the invention is the optical pickup according tothe above mentioned 3^(rd) aspect of the invention,

wherein one of said side faces of said convex portion is arranged on thesame plane as said end of said support holder or at a position locatingfurther inward than said end, and the other of said side faces of saidconvex portion is arranged on the same plane as said end of said supportholder or at a position locating further inward than said end, and

when said distance between said pair of parallel faces is defined as W,said width of said support holder in said direction of said right andleft ends is defined as X, and said distance of said support holdercapable of adjustment of positioning along said direction of said widthis defined as dx, relationship ofX−W≧2dx  (Expression 1)

is satisfied.

The 5^(th) aspect of the invention is the optical pickup according tothe above mentioned 3^(rd) aspect of the invention,

wherein when said distance between said pair of parallel faces isdefined as W, said width of said support holder in said directions ofsaid right and left ends is defined as X, and

when, regarding respective gaps between said convex portions and saidconcave portions of said support holder when adjustment of positioningon said optical base is performed with said support holder held on theair, said spacing before said adjustment of a gap at one end of saidsupport holder is defined as dx_(a), and said spacing before saidadjustment of a gap at said other end of said support holder is definedas dx_(b), relationship ofdx _(a) ≦dx _(b)  (Expression 2)andX−W≧2dx _(a)  (Expression 3)

Is satisfied.

Advantage of the Invention

According to the present invention, excellent signal characteristics canbe obtained for an optical disk on and/or from which recording and/orreproducing are performed using a laser.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing an optical configuration of an optical pickupin Embodiment 1 of the present invention.

FIG. 2( a) is a view showing a peripheral configuration of an opticaldetector 10 of the optical pickup in Embodiment 1 of the presentinvention, and FIG. 2( b) is a view showing the peripheral configurationof the optical detector 10 of the optical pickup in Embodiment 1 of thepresent invention.

FIG. 3( a) is a view showing an example of dimensions of the peripheralconfiguration of the optical detector 10 of the optical pickup inEmbodiment 1 of the present invention, and FIG. 3( b) is a view showingan example of dimensions of the peripheral configuration of the opticaldetector 10 of the optical pickup in Embodiment 1 of the presentinvention.

FIG. 4( a) is a view showing the positional relationship in theperipheral configuration of the optical detector 10 of the opticalpickup in Embodiment 1 of the present invention, FIG. 4( b) is a viewshowing application positions of adhesives 60 a and 60 b in theperipheral configuration of the optical detector 10 of the opticalpickup in Embodiment 1 of the present invention, FIG. 4( c) is a viewshowing application positions of the adhesives 60 a and 60 b in theperipheral configuration of the optical detector 10 of the opticalpickup in Embodiment 1 of the present invention, and FIG. 4( d) is aview showing application positions of the adhesives 60 a and 60 b in theperipheral configuration of the optical detector 10 of the opticalpickup in Embodiment 1 of the present invention.

FIG. 5( a) is a view showing a graph when characteristics of opticalpickups in Embodiment 1 of the present invention and a conventionalexample are evaluated by using changes in the value of focus offsetaccompanying temporal changes, and FIG. 5( b) is a view showing a graphwhen characteristics of the optical pickups in Embodiment 1 of thepresent invention and the conventional example are evaluated by usingchanges in FE asymmetry accompanying temporal changes.

FIG. 6 is a view showing an example of positional adjustment of asupport holder 30 of the optical pickup in Embodiment 1 of the presentinvention.

FIG. 7 is a view showing an example of positional adjustment of thesupport holder 30 of the optical pickup in Embodiment 1 of the presentinvention.

FIG. 8 is a view showing another example of the peripheral configurationof the optical detector 10 of the optical pickup in Embodiment 1 of thepresent invention.

FIG. 9( a) is a view showing a still further example of the peripheralconfiguration of the optical detector 10 of the optical pickup inEmbodiment 1 of the present invention, FIG. 9( b) is a view showing thestill further example of the peripheral configuration of the opticaldetector 10 of the optical pickup in Embodiment 1 of the presentinvention, and FIG. 9( c) is a view showing the still further example ofthe peripheral configuration of the optical detector 10 of the opticalpickup in Embodiment 1 of the present invention.

FIG. 10( a) is a view showing a peripheral configuration of an opticaldetector 10 of an optical pickup in Embodiment 2 of the presentinvention, FIG. 10( b) is a view showing the peripheral configuration ofthe optical detector 10 of the optical pickup in Embodiment 2 of thepresent invention, FIG. 10( c) is a view showing the peripheralconfiguration of the optical detector 10 of the optical pickup inEmbodiment 2 of the present invention, and FIG. 10( d) is a view showingthe peripheral configuration of the optical detector 10 of the opticalpickup in Embodiment 2 of the present invention.

FIG. 11 is a view showing a still further example of the peripheralconfiguration of the optical detector 10 of the optical pickup of eachembodiment of the present invention.

FIG. 12 is a view showing a still further example of the peripheralconfiguration of the optical detector 10 of the optical pickup in eachembodiment of the present invention.

FIG. 13 is a view showing a still further example of the peripheralconfiguration of the optical detector 10 of the optical pickup in eachembodiment of the present invention.

FIG. 14 is a view showing a still further example of the peripheralconfiguration of the optical detector 10 of the optical pickup in eachembodiment of the present invention.

FIG. 15 is a schematic sectional view of an optical information devicein Embodiment 3 of the present invention.

FIG. 16 is a schematic perspective view showing configuration of acomputer in Embodiment 4 of the present invention.

FIG. 17 is a schematic perspective view showing configuration of anoptical disk recorder in Embodiment 5 of the present invention.

FIG. 18 is a schematic perspective view showing configuration of anoptical disk player in Embodiment 6 of the present invention.

FIG. 19 is a schematic perspective view showing configuration of anoptical disk server in Embodiment 7 of the present invention.

FIG. 20 is a schematic perspective view showing configuration of a carnavigation system in Embodiment 8 of the present invention.

FIG. 21 is a view showing a configuration example of a conventionaloptical pickup.

FIG. 22 is a view showing a graph when characteristics of theconventional optical pickup are evaluated by using changes in value ofthe focus offset accompanying temporal changes.

FIG. 23 is a view for explaining cause of positional deviation of anoptical detector 210 in the conventional optical pickup.

FIG. 24 is a view for explaining the positional deviation of the opticaldetector 210 in the conventional optical pickup.

DESCRIPTION OF SYMBOLS

-   1 laser light source-   2 beam shaping element-   3 beam splitter-   4 collimating lens-   5 rising mirror-   6 condensing lens-   7 optical disk-   8 ¼ wavelength plate-   9 detection lens-   10 optical detector-   11 circuit board-   20 optical base-   21 a,21 b convex portion-   30 support holder-   31 a,31 b notch-   60 a,60 b adhesive-   100 optical pickup-   101 optical disk-   102 turntable-   103 clamper-   104 motor-   105 traverse-   106 control circuit-   107 optical disk drive-   110 personal computer-   111 optical disk drive-   120 optical disk recorder-   131 optical disk player-   140 optical disk server-   141 optical disk drive-   144 network-   150 car navigation system

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described withreference to the drawings.

Embodiment 1

An example of an optical system of an optical pickup in Embodiment 1 ofthe present invention is shown in FIG. 1. As for xyz axes shown in thisdrawing, the same reference numerals and directions are applied even inthe subsequent drawings.

In FIG. 1, reference numeral 1 designates a laser light source whichemits a laser beam of a wavelength λ, reference numeral 2 designates abeam shaping element which shapes a far-field pattern of the laser beam,reference numeral 3 designates a beam splitter which splits an opticalpath, reference numeral 4 designates a collimating lens, referencenumeral 5 designates a rising mirror which bends an optical axis,reference numeral 6 designates a condensing lens (optical lens), andreference numeral 7 designates an optical disk with a base materialthickness t1, in which recording/reproducing is performed by the lightbeam of the wavelength λ.

The laser light source 1 preferably uses a semiconductor laser lightsource, so that the size, weight, and power consumption of the opticalpickup and an optical information device using this optical pickup canbe reduced.

When the recording/reproducing of the optical disk 7 is performed, ablue light beam of a wavelength λ1 emitted from the laser light source 1is shaped by the beam shaping element 2, is reflected by the beamsplitter 3, and is made into substantially parallel beams by thecollimating lens 4. Further, the optical axis is bent by the risingmirror 5, and the parallel beams are made into circularly-polarizedlight by a ¼ wavelength plate 8. Then, the circularly-polarized light iscondensed on an information recording surface through a base material ofthe optical disk 7 with a thickness of 0.1 mm by a refractive condensinglens 6.

The blue light beam reflected by the information recording surfacetraces its original optical path reversely (return trip), is made intolinearly-polarized light in a direction perpendicular to its initialdirection by the ¼ wavelength plate 8, has a focal distance extended bythe collimating lens 4, is transmitted through or reflected by the beamsplitter 3, and enters the optical detector 10. By calculating theoutput of the optical detector 10, a servo signal and an informationsignal which are used for focus control or tracking control areobtained. As described above, as for the light beam of the wavelength λ,the beam splitter 3 is an optical path branch element with a polarizedlight separating film which totally reflects unidirectionallinearly-polarized light, and totally transmits linearly-polarized lightin a direction perpendicular thereto. These elements and holders (notshown) holding the elements are held on an optical base 20 (not shown).

Here, the optical detector 10 generally has a plurality of minutelight-receiving regions. The reflected light from the optical disk 7 ispropagated onto each light-receiving region to form a detection lightspot, and the aforementioned information signal is obtained by detectingthe quantity of light of the detection light spot and a modulationcomponent superimposed on a beam. That is, it is important that adetection spot reaches a minute light-receiving region withoutdeviation. Although elements which constitute the optical pickup arefixed on the optical base with high accuracy, it is extremely difficultto fix the elements without error. In addition, the semiconductor laserused for the laser light source 1 generally also has the positionalerror of a luminous point with respect to its housing. The opticaldetector itself also has the positional error of a light-receivingregion with respect to its housing. Accordingly, the optical detector 10requires adjustment of three axes of x, y, and z shown in FIG. 1, andshould be fixed in a floated state on the air by holding the opticaldetector using a jig (not shown). Although it is also possible to usethe adjustment axis of the optical detector itself as a substitutedepending on optical configurations, for example, by adjusting theposition of the laser light source 1 or adjusting the position of adetection spot on the optical detector 10 with high accuracy by thepositional adjustment of a detection lens 9, a triaxial adjustment ofthe optical detector 10 itself has an advantage that an adverse opticaleffect, such as deterioration of wave aberration, does not occur.

However, as already described, even if the optical detector 10 isadjusted and fixed with high accuracy, the present inventor hasdiscovered a problem in the optical pickup after manufacturing in thatthe positional deviation which is not negligible during the use of theBD may occur in the optical detector 10.

Thus, the cause of the positional deviation of the optical detector willbe discussed before essential parts of the optical pickup of thisembodiment 1 are described.

In a case where the convex portions 231 a and 231 b of the optical base230 have shapes such that the convex portions have stuck out from bothends of the mounting plate 220 as in the conventional technique shown inFIG. 21, it could be seen that the amount of positional deviation of theoptical detector 210 changes depending on the direction of radiation ofUV light to UV curable resin.

That is, as shown in FIG. 23, if adhesive that is a UV curable resin isapplied to four application points 240, 241, 242, and 243 between bothside faces of each of the convex portions 231 a and 231 b of the opticalbase 230 and end faces of the mounting plate 220, an optical fiber of aUV light radiation instrument is arranged in the right and leftdirections to radiate UV light, thereby curing the adhesive, the opticaldetector 210 always deviated downward after the curing of the adhesive,as shown by a broken line in FIG. 24. As a result of having studied thestructure of the optical fiber and the surroundings of the mountingplate 220 in detail, it was estimated that, since the optical fiberthrough which UV light is radiated deviated from a horizontal position,and the UV light was radiated in an obliquely downward direction from anobliquely upward direction, the upper adhesive might be cured early.

In order to demonstrate this estimation, the adhesive was cured suchthat the direction of the optical fiber was intentionally tilted upwardand UV light was radiated in an obliquely upward direction from anobliquely downward direction. As a result, as shown by a solid line inFIG. 24, the optical detector 210 deviated upward as estimated.

As such, in the structure of the conventional example, it can be seenthat, if the radiation position of UV light deviates even slightly froma horizontal position, the positional deviation of the optical detectormay occur in either upward or downward direction.

It is believed that the reason why the amount of positional deviation ofthe optical detector 210 changes depending on the direction of radiationof UV is as follows. As in FIG. 21, in a case where the convex portions231 a and 231 b of the optical base 230 have shapes such that the convexportions stick out outward from both ends of the mounting plate 220, UVlight is shielded by the convex portions 231 a and 231 b of the opticalbase 230 depending on its direction of irradiation, and casts a shadowover the adhesive. The cumulative quantity of light of the UV light inthe shadowed portion of the adhesive becomes significantly smallercompared to the portion directly irradiated with UV light. As a result,curing shrink variation occurs in the adhesive.

At this time, as variation occurs in the degree of curing shrink on theupper and lower sides of each of the convex portion 231 a and the convexportion 231 b, bias occurs in the stress applied to the mounting plate220 until the adhesive is completely solidified. In the example shown inFIG. 23, in a case where UV light is radiated from an oblique upperportion of the optical detector 210, a portion of the application point241 is hidden by the convex portion 231 a, and a shadow B which is notirradiated with UV light is formed. Similarly, a portion of theapplication point 243 is hidden by the convex portion 231 b, and ashadow B which is not irradiated with UV light is formed.

On the other hand, the application point 240 which makes a pair with theapplication point 241 is uniformly irradiated with UV light, andsimilarly, the application point 242 which makes a pair with theapplication point 243 is uniformly irradiated with UV light. In thisway, in each of the right and left application points, a differenceappears in curing reaction on the upper and lower sides.

As a result, it is believed that the positional deviation of the opticaldetector 210, an increase in focus offset accompanying the positionaldeviation, and deterioration of reproduction signal characteristics arecaused.

On the other hand, it is significantly difficult to suppress thepositional deviation of the optical detector 210 (or optical detector10) occurring in storage durability, i.e., with temporal changes,without variation by changing the application positions or applicationamount of an adhesive, and the physical properties or characteristics ofthe adhesive. Accordingly, in order not to exceed this allowable valuein total, it is necessary to minimize positional deviation in an initialcompletion state.

Under the above discussion, the present inventor realized theconfiguration of the optical pickup which reduces the positionaldeviation of the optical detector by suppressing variation in radiationof UV light. Hereinafter, a description will be made.

A perspective view of the structure around the optical detector 10 ofthe optical pickup of this embodiment 1 is shown in FIG. 2( a). A pairof convex portions 21 a and 21 b is provided on the optical base 20. Theconvex portions 21 a and 21 b are prismatic members which have arectangular cross-sectional shape in their drawing direction, and areformed integrally with the optical base 20. In addition, the supportholder 30 has a pair of notches 31 a and 31 b which is providedcorresponding to the position and shape of the convex portions 21 a and21 b, and is formed so as to pass through both principal planes, and theconvex portions 21 a and 21 b are arranged within the notches 31 a and31 b, respectively.

In addition, the optical detector 10 attached to the support holder 30is adjusted in three directions of x, y, and z shown in the coordinatein the drawing with respect to the optical base 20 together with thesupport holder 30, and as shown in FIG. 2( b), both ends of the supportholder 30 are fixed by adhesives 60 a and 60 b in the positions afteradjustment. If the optical base 20 and the support holder 30 are made ofa metal member, there is an advantage that the strength against impactcan be increased. Additionally, although the adhesives 60 a and 60 b maybe adhesives made of a photo-curable resin material, especially if theadhesives are made of UV-curable resin, not only thermal stability andimpact resistance are high, but also the time required for fixation canbe shortened. Therefore, there is also an advantage that theproductivity improves.

Next, an example of the dimensions of respective parts of the opticaldetector 10 is shown in FIGS. 3A and 3B. Especially, a cross-sectionalshape of the convex portion 21 a is a rectangle in which a long side is1.6 mm and a short side is 1.2 mm, and the surface of the notch 31 a andthe surface of the convex portion 21 a are arranged so as to maintain aunique distance of 0.5 mm in an arbitrary location. In addition,although the corners of the cross-section has roundness in the drawing,the corners are not limited by the machining profile of the corners(whether the corners are straight or curved) so long as the corners havea shape which has two sets of parallel faces as a rectangle.

Next, xy plane views around the optical detector, which show thearrangement relationship of the support holder 30, the convex portions21 a and 21 b, and the adhesives 60 a and 60 b that are UV-curableresins, are shown in FIGS. 4A to 4D.

FIG. 4( a) shows an example of the dimensional relationship immediatelybefore adjustment between the support holder 30 and the convex portions21 a and 21 b of the optical base 20 in the optical pickup of thisembodiment 1. The distance between side faces 21 a 1 and 21 b 1, whichdo not face the surfaces of the notches 31 a and 31 b of the supportholder 30, among the side faces of the two convex portions 21 a and 21 bis defined as W, and the width of the support holder 30 is defined as X.Also, among gaps between the convex portions 21 a and 21 b and thenotches 31 a and 31 b of the support holder 30, the spacing of a gapbetween the convex portion 21 b and the notch 31 b on the right in thedrawing as seen from the outside of the optical pickup of an x-directioncomponent is defined as dx₁, and the spacing of a gap between the convexportion 21 a and the notch 31 a on the left in the drawing is defined asdx₂. In addition, the spacings dx₁ and dx₂ before adjustment need to bevalues equal to or more than the maximum amount of adjustment dx bywhich the optical detector 10 needs to be adjusted in the x direction.

Here, it is desirable that the relationship of the following Expression(A) is satisfied between the distance W and the width X.(Expression 4)W≦X  (A)

That is, the distance W between the side faces 21 a 1 and 21 b 1 of theconvex portions 21 a and 21 b, which do not face each other, satisfiesthe relationship which becomes equal to or less than the width X of thesupport holder 30 in the direction of right and left ends.

The following advantages are obtained by adopting such a configuration.After the optical detector 10 which is held from the outside by a jigand is floated on the air along with the whole support holder 30 isadjusted with high accuracy, as shown in FIGS. 4B to 4D, the adhesives60 a and 60 b are applied so as to bridge between both ends of thesupport holder 30 and the convex portions 21 a and 21 b of the opticalbase 20, respectively.

Then, in a case where the UV light for curing the adhesives 60 a and 60b is radiated simultaneously on the right and left, the degree ofprojection of the side faces of the convex portions 21 a and 21 b issmall even if the radiation direction angle of the UV light has slightlydeviated from an ideal horizontal position. Therefore, the UV light isnot shielded by the convex portions 21 a and 21 b and is radiated on allthe regions of the adhesives 60 a and 60 b.

Here, a graph when characteristics of the optical pickup according tothis embodiment 1 are evaluated by using changes in value of focusoffset accompanying temporal changes is shown in FIG. 5( a), and a graphwhen the characteristics are evaluated by using the asymmetry of FEsignals accompanying temporal changes is shown in FIG. 5( b), each shownwith the case of the conventional example. In addition, the asymmetry ofan FE signal is an index expressed by (Aa−Ab)/2(Aa+Ab) when the upperamplitude of the FE signal is defined as Aa and the lower amplitudethereof is defined as Ab, with respect to a GND level.

As shown in FIG. 5( a), in both the conventional example and thisembodiment, ideal offset states are maintained immediately beforecompletion, i.e., after the completion of adjustment and before thecuring of adhesives. However, immediately after curing, a focus offsetof about 0.12 μm occurs in the conventional example, whereas the focusoffset in this embodiment is suppressed to be about 0.02 μm.

Moreover, when the optical pickups have been stored over the long termand have been subjected to progress experiments under the sametemperature conditions and humidity conditions as the case of FIG. 22,in this embodiment, the increase in focus offset is suppressed to about0.14 μm which falls below the allowable value of 0.2 μm of the BD.

Next, as shown in FIG. 5( b), in the conventional example, the asymmetryof FE signals deteriorates to about 13.5% after curing. In contrast, inthis embodiment, the asymmetry of FE signals is suppressed to about 0.2%after curing, and is suppressed to 16.0% after long-term storage. On theother hand, in the conventional example, the asymmetry of FE signalsafter long-term storage increases to higher than 25%.

As such, according to the optical pickup of this embodiment, the convexportions 21 a and 21 b and the support holder 30 are configured so thatthe radiation unevenness of UV light does not occur when the adhesivesare cured. Thereby, even if the adhesives 60 a and 60 b have been curedand shrinked, there is an advantage that the occurrence of deviationwhen the optical detector 10 is fixed is reduced to equal to or lessthan below an allowable range, and excellent signal characteristics canbe obtained. In addition, in this case, it is more preferable if theapplication positions of the adhesives are symmetrical in the horizontaldirection with respect to the optical detector 10.

Here, especially excellent points of a solution to the positionaldeviation of the optical detector 10 according to the embodiment asdescribed above will be further described by comparison with theconventional example.

In the conventional example shown in FIG. 21, since the convex portions231 a and 231 b have shapes such that the convex portions stick outoutward from both right and left ends of the mounting plate 220, aportion of the UV light radiated onto the adhesive is shielded. Thiscauses variation in curing shrink of the adhesives as described above.

Especially, since the convex portions 231 a and 231 b stick out at bothends, respectively, of the mounting plate 220, as shown in FIG. 23, theadhesives are split into upper and lower application points 240 and 241and upper and lower application points 242 and 243, which become fourpoints in total, at both right and left ends.

Accordingly, in the configuration of the conventional example, in orderto suppress the positional deviation of the optical detector 210, allthe plurality of application points 240 to 243 should be uniformly andsimultaneously irradiated with UV light. If not, the positionaldeviation of the optical detector 210 will certainly occur.

Only in the case where the irradiation is performed simultaneously onthe right and left from directions completely horizontal to thedirections of both ends of the mounting plate 220, simultaneousirradiation onto the application points 240 to 243 can be attained. Inthis case, only a minimum of two points are required as objects to besimultaneously irradiated. However, in this case, meticulous attentionis needed for the alignment for always maintaining the horizontaldirection. That is, as described in the discussion referred to FIG. 23,if the irradiation angle slightly deviates from the horizontaldirection, unevenness occurs in the irradiation regions, and adifference appears in the curing reaction on the upper and lower sidesin each of the right and left application points. Thereby, thepositional deviation of the optical detector during curing willcertainly occur.

Accordingly, for example, when optical pickups are mass-produced, a newproblem that productivity is significantly reduced may occur with thiscountermeasure because of the time and effort required for the alignmentbetween the optical fiber and the mounting plate.

On the other hand, in order to simultaneously irradiate four pointswithout taking the adjustment of alignment into consideration, it willbe necessary to make UV light radiated using four UV light radiationapparatuses, or from an optical fiber branched into four pieces from oneor a plurality of UV-light radiation apparatuses. As a result, a newproblem that the apparatus is enlarged may occur in any case.

As such, as long as the configuration of the conventional example isused, the solution to the positional deviation of an optical detectorhas problems that the difficulty of implementation or a new problemaccompanying the implementation occurs. In contrast, this embodiment hasmarked advantages that the positional deviation of an optical detectorcan be reliably suppressed without causing a new problem, by a simplerconfiguration including changes in the shape of the convex portions 21 aand 21 b and changes in the positional relationship between the convexportions 21 a and 21 b and the support holder 30.

Moreover, the conditions of respective parts for optimizing theconfiguration of the optical pickup of this embodiment will beconcretely described.

As described with reference to FIG. 4( a), the spacing dx₁ and spacingdx₂ before adjustment are determined to be values equal to or more thanthe maximum amount of adjustment dx such that the optical detector 10can be adjusted in the x direction. However, in order to maintain themechanical strength of the support holder 30, it is desirable that thevalue of the amount of adjustment dx is as small as possible.

Moreover, it is desirable that the relationship of the followingExpression (B) is satisfied among the amount of adjustment dx, thedistance W, and the width X.(Expression 1)X−W≧2dx  (B)

By adopting such a configuration, even if the support holder 30 is movedto the right (left) to the maximum amount of adjustment dx when theoptical detector 10 is adjusted, the side face 21 a 1 of the convexportion 21 a, which does not face the support holder 30, does notprotrude further outward than a left end face 30 a (right end face 30 b)of the support holder 30. This relationship is expressed by Expression(X/2)−dx≧(W/2), a modification of which coincides with Expression (B).

Accordingly, there is more reliably obtained the advantage thatdeviation during the fixation of the optical detector 10 is eliminatedby no occurrence of radiation unevenness during the aforementioned UVradiation after the application of the adhesives 60 a and 60 b.

Additionally, in this case, the value of a smaller one of the spacingdx₁ and spacing dx₂ before adjustment is made to coincide with theamount of adjustment dx. By making the spacing before adjustment smallto an adjustment value dx, the support holder 30 contacts the convexportion 21 a (or 21 b) at the maximum value of the amount of adjustmentdx in the x direction, and the convex portion 21 b (or 21 a) functionsas a stopper for keeping the support holder 30 from moving beyond theamount of adjustment dx. By adopting such a configuration, there is anadvantage that higher accuracy and higher-speed adjustment can beattained, and productivity improves.

Here, FIG. 6 shows the state of the optical pickup after the adjustmentof moving the support holder 30 in the −x direction with the maximumamount of adjustment dx=dx₁ with respect to the spacing dx₁ is performedin a case where the support holder 30 and the convex portions 21 a and21 b are prepared on the condition of X>W according to Expression (A),the spacing of the gap between the convex portion 21 b and the notch 31b before adjustment is defined as dx₁, and the spacing of the gapbetween the convex portion 21 a and the notch 31 a is defined as dx₂(dx₂>dx₁).

As shown in FIG. 6, the notch 31 b of the support holder 30 contacts theconvex portion 21 b and does not move in the −x direction any more. Inaddition, since the end face 30 a of the support holder 30 where thenotch 31 a is provided and the side face 21 a 1 of the convex portion 21a are arranged on the same plane, a configuration in which the convexportion 21 a protrudes like the conventional example is hindered.

Next, FIG. 7 shows the state of the optical pickup after the adjustmentof moving the support holder 30 in the −x direction with the maximumamount of adjustment dx=dx₁ with respect to the spacing dx₁ is performedin a case where, similarly to FIG. 4( a), the support holder 30 and theconvex portions 21 a and 21 b are prepared on the condition of X=Waccording to Expression (A), the spacing of the gap between the convexportion 21 b and the notch 31 b before adjustment is defined as dx₁, andthe spacing of the gap between the convex portion 21 a and the notch 31a is defined as dx₂ (dx₂>dx₁). In this case, the side face 21 a 1 of theconvex portion 21 a, which does not face the surface of the notch 31 a,protrudes outward by dx₁ with respect to the end face 30 a of thesupport holder 30. On the other hand, on the right end face of thesupport holder 30, the convex portion 21 b is arranged inside the notch31 b so as to retreat by the spacing dx₁ of a gap corresponding to theamount of adjustment dx.

However, even when any deviation has occurred between the side face ofthe convex portion 21 a (or 21 b) and either right or left end face ofthe support holder 30, when the size of the deviation is in the amountof adjustment dx, the deviation can be treated as an error, and theadvantages of the present invention are not impaired. Because that themaximum value that the amount of adjustment dx takes is set to about 200to 300 μm as compared to the dimensions of the respective parts shown inFIG. 3, however, in this configuration, the positional deviation of theoptical detector 10 to be generated when the adhesives 60 a and 60 b arecured according to the value of dx is about 1 μm, and the focus offsetchange at that time is merely about 0.01 μm. Even if the storagedurability is taken into consideration in addition to this, it ispossible to sufficiently suppress the threshold value to 0.2 μm or lesssuch that an excellent reproduction signal can be obtained. In the caseof FIG. 7, since the protruding degree of the side face 21 a 1 of theconvex portion 21 a from the side face 30 a of the support holder 30 isdx₁=dx, this requirement is satisfied. In addition, since the degree towhich the convex portion 21 b exists further inward than the right sideface of the support holder 30 is also dx₁=dx, this requirement issatisfied.

In addition, even in the configuration example shown in FIG. 6, theconvex portion 21 b is arranged further inward than the spacing beforeadjustment on the right end face of the support holder 30. However,since the relationship of dx₁=dx is maintained, the above requirement issatisfied. In addition, in the above description, as for the arrangementof the side face 21 a 1 of the convex portion 21 a, the side near theoptical detector 10 was defined as the inside, and the side far from theoptical detector 10 was defined as the outside.

Additionally, in the above description, the spacing of the gap betweenthe convex portion 21 b and the notch 31 b before adjustment was definedas dx₁, and the spacing of the gap between the convex portion 21 a, andthe notch 31 a is defined as dx₂ (dx₂>dx₁). However, generally, whichone of the two spacings is larger is arbitrary. Accordingly, withrespect to one spacing, when the spacing before adjustment at one endface of the support holder 30 is defined as dx_(a), and the spacingbefore adjustment at the other end face of the support holder 30 isdefined as dx_(b),(Expression 2)dx _(a) ≦dx _(b)  (C)and(Expression 3)X−W≧2dx _(a)  (D)

need to be established. In addition, the example shown in FIG. 4( b) isa configuration in which adjustment is completed by Width X=Distance W,Amount of Adjustment dx=0, and Spacing dx₁=dx₂, and satisfies all theconditions of the above (A) to (D).

Next, the application points of the adhesives 60 a and 60 b will bedescribed with reference to FIGS. 4B to 4D.

In the case of a configuration in which the application positions of theadhesives 60 a and 60 b are such that the adhesives are kept fromflowing into the gaps between the convex portions 21 a and 21 b and thenotches 31 a and 31 b of the support holder 30 as in FIG. 4( b), thereis an advantage that the balance deviation of curing shrink caused byradiation of UV light mostly hardly occurs, and the positional deviationof the optical detector 10 during fixation hardly occurs.

In addition, in the case of a configuration in which a small amount ofadhesives flow into the gaps as in FIG. 4( c), while the balancedeviation of curing shrink is suppressed to the minimum, there is anadvantage that the area of adhesion between the convex portions 21 a and21 b and the support holder 30 increases, thereby enhancing the holdingstrength of the support holder 30.

Additionally, in the case of a configuration in which the adhesives 60 aand 60 b flows into the gaps so as to fill the gaps as in FIG. 4( d),the holding strength of the support holder 30 is high, and it is alsopossible to adopt a configuration in which the spacings dx₁ and dx₂ ofthe gaps are made small so that the curing shrink balance deviation issuppressed to the minimum. In addition, in the case of a configurationof FIGS. 4C and 4D in which the adhesives 60 a and 60 b flow into thegaps, when adhesives having anaerobic properties which starts anadvantage reaction as the adhesives are not touched by air are used asthe adhesives 60 a and 60 b, there is an advantage that the portion thatUV light does not reach can also be reliably cured, and the holdingstrength of the support holder 30 can be further enhanced.

In addition, in the configuration example shown in FIG. 6, either theconvex portion 21 a or the convex portion 21 b may protrude from bothends of the support holder 30. However, as shown in FIG. 7 or respectivedrawings of FIGS. 4A to 4D, it is more desirable that the convexportions 21 a and 21 b exist at the same positions as both ends of thesupport holder 30 or further inward than both ends. This is because,especially as shown in FIG. 4( b), the adhesives 60 a and 60 b moreeasily bridge, i.e., more easily become integral on the upper and lowersides of the convex portions 21 a and 21 b if the convex portions existfurther inward than both ends. Ina case where the convex portionsprotrude from the support holder 30, even if the influence of shieldingof UV light fall within a range of error as mentioned above, there is apossibility that curing unevenness may occur unless the adhesivesbridge.

Additionally, in the case of a configuration in which the adhesives 60 aand 60 b are respectively applied to the positions of both right andleft end faces of the support holder 30 as in this embodiment 1, theportions applied at the positions of both the right and left endsgreatly contribute to the holding of the support holder 30, andcontribution of the portions which have flowed into the gaps between thenotches 31 a and 31 b of the support holder 30 and the convex portions21 a and 21 b is not great.

Accordingly, for example, like a configuration shown in FIG. 8, even ifa circuit board 11 which transmits an output signal of the opticaldetector 10 is arranged at a position on the support holder 30 such thatthe convex portions 21 a and 21 b are covered, it is possible to firmlyfix the support holder 30.

Here, xz plane views around the optical detector are shown in FIGS. 9Ato 9C. In FIG. 9, dz represents the gap spacing between the supportholder 30 and the optical base 20 when the light-receiving region of theoptical detector 10 is in an arrangement as designed, T represents thethickness of the support holder 30 in the z direction, and H representsthe height of the convex portion 21 in the z direction. Here, it isdesirable that the relationship of the following Expression (E) issatisfied among the spacing dz, the thickness T, and the height H.(Expression 5)H≦dz+T  (E)

By adopting such a configuration, the convex portions 21 a and 21 b arekept from protruding further than the surface of the support holder 30in the z direction. For this reason, parts can be freely arranged withinthe surface of the support holder 30 on the side of the optical detector10. As a result, for example, as shown in FIG. 9( c), there is anadvantage that a circuit board having a sufficient thickness can be usedas the circuit board 11.

Additionally, although the adhesive 60 is mainly UV-curable resin,especially resins having higher viscosity during non-curing are morepreferable. Especially, the viscosity is preferably 20000 mPa·s or more.By using such an adhesive, even if the adhesives 60 a and 60 b areapplied to the support holder 30 and the convex portions 21 a and 21 bafter positional adjustment of the optical detector 10, not only asituation where the adhesives running down due to gravity can beavoided, but also the adhesives 60 a and 60 b can be prevented fromflowing into the gaps between the notches 31 a and 31 b of the supportholder 30 and the convex portions 21 a and 21 b, and the portions whichare not cured by the radiation of UV light can be minimized.Accordingly, there is an advantage that the reliability against anypositional deviation after fixation improves.

Additionally, in the configuration of this embodiment 1, the supportholder 30 is held with respect to the optical base 20 only via theadhesives 60 a and 60 b in a floated state on the air. Therefore, if thestrength after curing of the adhesives 60 a and 60 b is low, there is aproblem that the optical detector 10 may cause positional deviation inthe whole support holder 30 due to a physical external force. In orderto deal with this problem, it is desirable that the adhesives 60 a and60 b has a hardness (Shore D) after curing of equal to or greater than60 and equal to or less than 90. If the hardness is 60 or less, forexample, even if an external force, such as the tension of a flexibleprinted board which transmits an output signal of the optical detector10, is weak, the optical detector 10 may cause positional deviationgradually in the whole support holder 30 as the external force continuesto be applied. Additionally, if the hardness is as high as 90 or more,when an instantaneous impact of about 300G to 500G is applied to thewhole optical pickup, the adhesives are not able to bear the loadgenerated due to the weight of the support holder 30 and the opticaldetector 10 itself, and the adhesives after curing cause a defect, suchas cracking. If the hardness is equal to or greater than 60 and equal toor less than 90, problems do not occur, and the optical detector 10 andthe support holder 30 can be stably held.

As described above, according to the optical pickup of this embodiment1, positional deviation of the optical detector 10 caused by the curingshrink of the adhesives 60 a and 60 b during curing by UV-lightradiation can be made small by using the small support holder 30.

Accordingly, an advantage that an adjusting/fixing device for theoptical detector can be miniaturized at low cost is obtained.Additionally in a case where optical pickups are mass-produced, anadvantage that the maintenance of the adjusting/fixing device for theoptical detector is also easy, and productivity improves is alsoobtained.

Embodiment 2

A perspective view of the structure around the optical detector 10 ofthe optical pickup in this embodiment 2 is shown in FIG. 10( a).Configurations other than those shown in this drawing are the same asthose in Embodiment 1, and their functions and advantages are also thesame as those shown in Embodiment 1.

As shown in FIG. 10( a), the optical pickup of this embodiment 2 ischaracterized in that a cut-in portion 32 a of the support holder 30becomes a depression which does not pass through the whole thickness inthe z direction, i.e., both the principal planes, and is formed over onesurface and side face of the support holder 30. Although not directlyshown in this drawing, another cut-in portion 32 b also has the sameconfiguration. Accordingly, as shown in FIG. 10( c), as seen from the xyplane, the convex portions 21 a and 21 b are in the state of beinghidden by the surface of the support holder 30 and are not exposed tothe outside. In addition, in the drawing, the profiles of the cut-inportions 32 a and 32 b are shown by broken lines.

By including the above feature, this embodiment 2 has the followingadvantages. In a case where the notches have passed through the wholethickness of the support holder 30 in the z direction as in the notches31 a and 31 b of the support holder 30 in Embodiment 1, the mechanicalstrength of the support holder 30 cannot be made high. Therefore, forexample, in a case where the impact of high G (acceleration) is applied,there is a probability that deformation of the support holder 30 itselfoccurs.

On the other hand, according to the configuration of this embodiment 2,there are advantages that the mechanical strength is enhanced withoutenlarging the support holder 30, all the configurations described inEmbodiment 1 can be adopted, and the support holder 30 can be stablyfixed to the optical base 20 via the adhesives 60 a and 60 b in afloated state on the air.

In addition, in the above Embodiments 1 and 2, the optical detector 10is equivalent to the optical component of the present invention, thesupport holder 30 is equivalent to the support holder of the presentinvention, the optical base 20 is equivalent to the optical base of thepresent invention, and the notches 31 a and 31 b, and the cut-inportions 32 a and 32 b are equivalent to the concave portions of thepresent invention.

In addition, in the above Embodiments 1 and 2, especially, the method offixing the support holder 30 which supports the optical detector 10 hasbeen described. However, all the same advantages are obtained if thestructure of the present invention is used even for fixation of a lens,a prism, a passive element like a diffraction grating, an active elementlike a laser diode or a photodiode, and other arbitrary opticalcomponents, as parts which require fixation by adhesives in a floatedstate on the air in various parts of the optical pickup which requireshigh-accuracy adjustment and fixation.

Especially, in a case where parts made of materials having low opticaltransparency are used or in a case where optical component are attachedto a holder made of metal or resin having low optical transparency andthe holder is adhered and fixed in a floated state on the air, thestructure of the present invention can exhibit marked advantages.

Additionally, as for the optical configuration of the optical pickup,the system shown in FIG. 1 is an example. Even if any kind of opticalsystem is used, all the same advantages are also obtained if thestructure of the present invention is used as a structure which fixes anoptical component held by a jig (not shown) in a floated state on theair for adjustment, etc.

In addition, although the convex portions 21 a and 21 b of the opticalbase 20 have a rectangular cross-sectional shape in the drawingdirection in the above embodiments 1 and 2, the convex portions may haveother shapes. As an example, as shown in FIG. 11, a configuration usingthe convex portions 22 a and 22 b having a pentagonal cross-sectionalshape is shown.

The cross-sectional shape of the convex portion 22 a has protrudingportion 23 a formed by a pair of opposed oblique faces on the side facewhich does not face the notch 31 a described in Embodiments land 2.Since the protruding portions 23 a and 23 b incline with respect to thex-axis and the y-axis, even in a case where the radiation angle of UVlight has deviated from the ideal horizontal position obliquely upwardor obliquely downward, the dead angle which shields the UV light hasdecreased as compared with the case of the rectangular cross-section.Thus, it is possible to make UV light uniformly irradiate the adhesives.

At this time, in each of the protruding portions 23 a and 23 b, it isdesirable that the distance between imaginary lines 22 a 1 and 22 b 1which join points where the roots of the oblique faces are connected isequivalent to the distance W in Embodiment 1. That is, the protrudingportions 23 a and 23 b have a configuration which is further added tothe side faces 21 a 1 and 21 b 1 of the convex portions 21 a and 21 b inEmbodiment 1. In this case, the convex portions 22 a and 22 b can take agreater horizontal width than the amount of adjustment dx, and canincrease physical strength.

In addition, although the protruding portions 23 a and 23 b have beenformed by a pair of opposed oblique faces, the same advantages areobtained even if they are constituted as convex portions 24 a and 24 bwhich have curved faces 25 a and 25 b which are positively bent, asshown in FIG. 12. In this case, the distance between the imaginarysurface 24 a 1 and 24 b 1 which connects faces where the roots of thecurved faces 25 a and 25 b are connected is equivalent to the distance Win Embodiment 1.

In addition, in the above description, the convex portions 21 a and 21 bhave a rectangular cross-section, etc. However, as shown in FIG. 13, theconvex portions may be realized as convex portions 26 a and 26 b havinggrooves 27 a and 27 b provided in their drawing direction formed ontheir surfaces, respectively. In this case, since applied adhesives 60 aand 60 b flow into the grooves 27 a and 27 b therealong, there is anadvantage that the adhesives are prevented from flowing into the gapsbetween the convex portions 26 a and 26 b and the notches 31 a and 31 bof the support holder 30, and the configuration shown in FIG. 4( b) ismore easily realized.

Similarly, a configuration example in which the adhesives are preventedfrom flowing into the gaps is shown in FIG. 14. As shown in FIG. 14,notches 33 a and 33 b of the support holder 30 have banks 33 a 1 and 33b 1 on the upper and lower sides thereof, while convex portions 28 a and28 b of the optical base 20 also have banks 28 a 1 and 28 b 1 on theupper and lower sides thereof, respectively. In the gaps, since thespacing of a portion where the banks 33 a 1 and 28 a 1 face each otherand the spacing of a portion where the banks 33 b 1 and 28 b 1 face eachother become smaller than other portions, the adhesives can be preventedfrom flowing into the deep sides of the gaps. In addition, the banks 33a 1 and 33 b 1 on the side of the support holder 30 may be omitted.

In addition, although the convex portions 21 a and 21 b are metallicmembers formed integrally with the optical base 20 in the abovedescription, the convex portions may be separate members using a resinmaterial. In this case, if a transparent resin material is used as theresin material, it is possible to further reduce the influence ofshielding of UV light by the convex portions. This advantage is able tofurther reinforce the surfaces of the notches 31 a and 31 b of thesupport holder 30 by performing reflecting processing of a specularsurface, etc.

In addition, in the above description, a pair of convex portions 21 aand 21 b is provided corresponding to the notches 31 a and 31 b of thesupport holder 30 provided at both the right and left ends,respectively. However, a configuration in which two or more notches areprovided at both the right and left ends, and convex portions of anumber corresponding to these notches are provided may be adopted.

Embodiment 3

Moreover, an embodiment of an optical information device using theoptical pickup of the present invention is shown in FIG. 15. Aconfiguration example of a whole optical disk drive 107 serving as anoptical information recording/reproducing device is shown in FIG. 15. Anoptical disk 101 is sandwiched and fixed by a turntable 102 and aclamper 103, and is rotated by a motor (rotational system) 104 servingas the motor of the present invention. An optical pickup 100 describedin either Embodiment 1 or Embodiment 2 rides on a traverse (transfersystem) 105 so that the light to be radiated can be moved from the innerperiphery of the optical disk 101 to the outer periphery thereof. Acontrol circuit 106 serving as the electric circuit of the presentinvention performs focus control, tracking control, traverse control,rotation control of a motor, etc. on the basis of a signal received fromthe optical pickup 100. Additionally, reproduction of information from areproduction signal and delivery of a recording signal to the opticalpickup 100 are performed.

Embodiment 4

An embodiment of a computer including the optical disk drive (opticalinformation recording/reproducing device) described in Embodiment 3 isshown in FIG. 16.

In FIG. 16, a personal computer (computer) 110 includes the optical diskdrive 107 in Embodiment 3, a keyboard 113 serving as the input device ofthe present invention for performing input of information, and a monitor112 serving as the output device for performing display of information.

The computer including the optical disk drive of the above-describedEmbodiment 3 as an external storage device has the advantages capable ofstably recording or reproducing information on or from different kindsof optical disks and performing arithmetic processing on the basis ofthe reproduced information, and capable of being used for a wide rangeof applications. In addition, an arithmetic device (CPU) for arithmeticprocessing (not shown) built in the personal computer 110 is equivalentto the arithmetic device of the present invention.

The optical disk drive 107 is able to take advantage of thelarge-capacity property thereof, thereby taking backup of a hard diskwithin the computer, using media (optical disks) inexpensively, andcarrying the media (optical disk) easily, and is able to take advantageof its compatibility that information can be read even in other opticaldisk drives, thereby exchanging programs and data with people, orcarrying the optical disk drive for private use. Additionally, it isalso possible to cope with reproducing/recording of existing media, suchas DVDs and CDs. In addition, in a case where connection with thekeyboard 113 and the monitor 112 is released, an input terminal forconnection with the keyboard 113 and an output terminal for connectionwith the monitor 112 are respectively provided as the input terminal andoutput terminal of the present invention on the main body of thepersonal computer 110.

Embodiment 5

An embodiment of an optical disk recorder (video recording/reproducingapparatus) including the optical disk drive (optical informationrecording/reproducing device) described in Embodiment 3 is shown in FIG.17.

In FIG. 17, the optical disk recorder 120 has built therein the opticaldisk drive 107 (not shown) in Embodiment 3, an encoder (not shown)serving as the encoder of the present invention which converts imageinformation into information in order to perform recording on an opticaldisk within the optical disk drive 107, and a decoder (not shown)serving as the decoder of the present invention which converts theinformation within the optical disk into image information, and is usedin connection with the monitor 121 for displaying recorded pictures.

The optical disk recorder 120 including the optical disk drive 107 ofthe above-described Embodiment 3 has the advantages capable of stablyrecording or reproducing pictures on or from different kinds of opticaldisks and is capable of being used for a wide range of applications. Theoptical disk recorder is able to record pictures on media (opticaldisk), and whenever a user wants, reproduce the pictures. In an opticaldisk, the operation of rewinding after recording and reproducing isunnecessary unlike a tape, and the chasing reproduction of reproducing ahead portion of a certain program while the program is recorded or thesimultaneous recording/reproducing of reproducing a previously recordedprogram while a certain program is recorded become possible. It ispossible to take advantage of using media inexpensively, carrying mediaeasily, and its compatibility in that information can be read even inother optical disk recorders, thereby exchanging recorded pictures withpeople, or carrying the optical disk for private use. Additionally, theoptical disk recorder also copes with reproducing/recording of existingmedia, such as DVDs and CDs.

In addition, although the case where only an optical disk drive isprovided has been described herein, a hard disk may be built in and avideo recording/reproducing function of a videotape may be built in. Inthat case, temporary saving of pictures and backup can be performedeasily.

Embodiment 6

An embodiment of an optical disk player (video reproducing apparatus)including the optical disk drive (optical informationrecording/reproducing device) described in Embodiment 3 is shown in FIG.18.

In FIG. 18, an optical disk player 131 including an LCD monitor 130 hasbuilt therein the optical disk drive 107 (not shown) in Embodiment 3,and a decoder (not shown) serving as the decoder of the presentinvention which converts the information within an optical disk intoimage information, and is able to display the picture recorded on theoptical disk on the LCD monitor 130. The optical disk player includingthe optical disk drive 107 of the above-described Embodiment 3 has theadvantages capable of stably reproducing pictures from different kindsof optical disks and capable of being used for a wide range ofapplications.

The optical disk player is able to reproduce pictures recorded on media(optical disk), whenever a user wants. In an optical disk, the operationof rewinding after reproducing is unnecessary unlike a tape, and it ispossible to make an access to an arbitrary location of a certain pictureto reproduce the picture. Additionally, the optical disk player alsocopes with reproducing of existing media, such as DVDs and CDs.

Embodiment 7

An embodiment of an optical disk server including the optical disk drive(optical information recording/reproducing device) described inEmbodiment 3 is shown in FIG. 19.

In FIG. 19, the optical disk server 140 includes the optical disk drive107 in Embodiment 3, a monitor 142 for displaying information, and akeyboard 143 for performing input of information, and is connected witha network 144 via an interface (not shown) serving as the input/outputterminal of the present invention.

The optical disk server 140 including the optical disk drive 107 of theabove-described Embodiment 3 as an external storage device has theadvantages capable of stably recording or reproducing information on orfrom different kinds of optical disks and capable of being used for awide range of applications. The optical disk drive takes advantage ofthe large-capacity property thereof, thereby sending out information(such as images, voices, pictures, HTML documents, and text documents)recorded on an optical disk according to the request from the network144. Additionally, the optical disk drive records information sent fromthe network on a requested location. Additionally, since informationrecorded on existing media, such as DVDs and CDs, can also bereproduced, it is also possible to send out the information.

Embodiment 8

An embodiment of a car navigation system including the optical diskdrive (optical information recording/reproducing device) described inEmbodiment 3 is shown in FIG. 20.

In FIG. 20, the car navigation system 150 has built therein the opticaldisk drive 107 (not shown) in Embodiment 3 and an decoder (not shown)serving as the decoder of the present invention which converts theinformation within the optical disk into image information, and is usedin connection with an LCD monitor 151 for performing display oftopography or destination information.

The car navigation system including the optical disk drive 107 of theabove-described Embodiment 3 has the advantages capable of stablyrecording or reproducing pictures on or from different kinds of opticaldisks and capable of being used for a wide range of applications. Thecar navigation system 150 plots the current position on the basis of mapinformation recorded on media (optical disk), and the information of aglobal positioning system (GPS), a gyroscope, a speedometer, anodometer, etc., and displays the position on an LCD monitor.Additionally, when a destination is input, an optimal path to thedestination is plotted on the basis of map information or roadinformation, and is displayed on the LCD monitor.

By using a large-capacity optical disk in order to record mapinformation, one disk can cover a wide area and provide detailed roadinformation. Additionally, information on restaurants, conveniencestores, gas stations, etc. which pertain to the vicinities of roads canalso be simultaneously stored on the optical disk, and can be provided.Moreover, as time goes by, the road information becomes old and does notmatch reality. However, since optical disks are compatible and media areinexpensive, the newest information can be obtained by replacing an oldoptical disk with a disk on which new road information is stored.Additionally, since the car navigation system copes withreproducing/recording of existing media, such as DVDs and CDs, it isalso possible to see a film in an automobile or to listen to music.

INDUSTRIAL APPLICABILITY

The present invention has the advantages that excellent signalcharacteristics can be obtained for optical disks on and/or from whichrecording and/or reproduction are performed using a laser, and can beutilized in the broad industrial field from computers to AV equipmentutilizing optical disks, and the industrial applicability thereof isvery wide and great.

1. An optical pickup comprising: an optical component; a support holderfor holding said optical component; and an optical base for fixing saidsupport holder, wherein said optical base has a plurality of convexportions, said optical base and said support holder are fixed byphoto-curable adhesives for adhering said convex portions and saidsupport holder to each other, and a height of said convex portions is aheight such that said convex portions do not protrude from said supportholder in a direction of an optical axis of a beam which enters saidoptical component.
 2. The optical pickup according to claim 1, whereinsaid support holder has at least one concave portion at its ends.
 3. Theoptical pickup according to claim 1, wherein application positions ofsaid photo-curable adhesives are symmetrical to each other in a verticaldirection and a horizontal direction about center of a light-receivingregion of said optical component.
 4. The optical pickup according toclaim 2, wherein said concave portions of said support holder formnotches which pass through both surfaces of said support holder.
 5. Theoptical pickup according to claim 2, wherein said concave portions ofsaid support holder are formed only in a surface side of said supportholder which faces said convex portions.
 6. The optical pickup accordingto claim 1, wherein said convex portions are hidden inside an externalshape of said support holder in a projection view seen from a drawingdirection of said convex portion.
 7. The optical pickup according toclaim 1, wherein said convex portions have grooves or banks providedalong a drawing direction from said surface of said optical base.
 8. Theoptical pickup according to claim 1, wherein said convex portions areformed from a transparent material.
 9. The optical pickup according toclaim 2, wherein said convex portions are formed from a transparentmaterial, faces of said concave portions which faces said convexportions are subjected to reflecting processing.
 10. The optical pickupaccording to claim 1, wherein said adhesive has a viscosity of 20000mPa·s or more in a gel state during non-curing.
 11. The optical pickupaccording to claim 1, wherein hardness of said adhesive after curing isequal to or greater than 60 and equal to or less than 90 in Shore Dscales.
 12. The optical pickup according to claim 1, wherein saidoptical component is an optical detector which receives a light beamemitted from a light source and reflected by an optical disk.
 13. Anoptical information device comprising: said optical pickup according toclaim 1, a motor which turns an optical disk, and an electric circuitwhich receives a signal obtained from said optical pickup, and controlsor drives said motor and said optical pickup on said basis of saidsignal.
 14. A computer comprising: the optical information deviceaccording to claim 13, an input device or input terminal for inputtinginformation, an arithmetic device which performs calculation on saidbasis of information input from said input device or input terminal, orinformation reproduced from said optical information device, and anoutput device or output terminal for displaying or outputting saidinformation input from said input device or input terminal, saidinformation reproduced from said optical information device, or resultscalculated by said arithmetic device.
 15. An optical disk playercomprising: the optical information device according to claim 13, and adecoder from information to an image, which converts an informationsignal obtained from said optical information device into an image. 16.A car navigation system comprising: the optical information deviceaccording to claim 13, and a decoder from information to an image, whichconverts an information signal obtained from said optical informationdevice into an image.
 17. An optical disk recorder comprising: theoptical information device according to claim 13, and an encoder fromsaid image to information, which converts image information intoinformation to be recorded by said optical information device.
 18. Anoptical disk server comprising: the optical information device accordingto claim 13, and an input/output terminal which performs exchange ofinformation with outside.